An indirect contact type heat exchanger for a cooling tower is widely used as a closed type heat exchanger or such a type of heat exchangers that it is mounted on a packing material consisting of a large number of corrugated plates in a parallel arrangement to prevent generation of whitish smoke or mist. An example of the inner structure of the heat exchanger is shown in FIGS. 24 to 26 in which air passages for feeding air in the horizontal direction are separated by metallic plates or synthetic resin plates from liquid-flowing passages for feeding liquid in the vertical direction so that the two kinds of passages are arranged alternately. Heat-exchanging efficiency is increased by reducing the space of the liquid-flowing passages as much as possible. In each of the liquid-flowing passages, there are formed a number of deflectors projecting from the partition plates in the liquid-flowing passages to reduce a flow speed of the liquid to thereby further increase heat-exchanging efficiency.
Japanese Unexamined Patent Publication No. 100370/1976 discloses a heat exchanger for cooling tower which comprises a plurality of thin, flat liquid-flowing passages arranged vertically and in parallel to each other and a plurality of thin, flat air-flowing passages extending vertically which are alternately interposed between the adjacent liquid-flowing passages, wherein each of the liquid-flowing passages is separated from each of the air-flowing passages by a heat exchanging partition plate made of a synthetic resin so that the liquid and air are fed in the passages in a non-contact state. Both walls for forming of each of the air-flowing passages are formed by an inverse U-shaped member. The adjacent inverse U-shaped members are connected to each other by means of ribs projecting from the side walls so that a liquid-flowing passage is formed between the connected inverse U-shaped members.
The heat exchanger disclosed in the above-mentioned publication is mounted on a cooling tower by hanging a plurality of the inverse U-shaped members above the packing material held in the cooling tower by means of a horizontal supporting beam as shown in FIG. 27, or it is mounted on a cooling tower by hanging a plurality of vertically arranged heat exchangers inside the packing material which is disposed at an outer air inlet port of the cooling tower as shown in FIG. 28. This arrangement of the heat exchangers is to prevent generation of whitish smoke or mist in the winter season.
In the conventional heat exchangers, however, there is such a disadvantage that, when it is used for a long time, dust or microorganisms deposit on the wall surface of the liquid-flowing passages which are generally narrow and are curved in order to reduce the falling speed of the liquid flowing by the action of gravity. As a result, the optimum flow rate of liquid can not be obtained, and there often causes flooding of the liquid at the liquid supplying side of the heat exchanger. This results in not only wetting the heat exchanger but also reduction of an amount of a refrigerant circulated in the heat exchanger.
In a case that the heat exchanger is used for a cooling tower by disposing it above the packing material to disperse the liquid discharged from the heat exchanger onto the packing material, the quantity of the dispersed liquid (water) becomes short to thereby invite the shortage of liquid circulating in the cooling tower.
In such a type of cooling tower that a plurality of the heat exchangers are supported by hanging them in a multi-stage at the inside of the packing material which is disposed at the outer air inlet port of the cooling tower (FIG. 28), the shortage of the liquid in the cooling tower results in the generation of whitish smoke or mist.